Department of Invertebrate Zoology

Coral

The NMNH coral collection is arguably the largest, most important, and best documented in the world, particularly in the realm of deep-water species. Corals, loosely defined, include stony corals, octocorals, black corals, and hydrocorals, constituting approximately 4,820 species. Sixty-five per cent of those species, or about 3,150, occur in deep water. This is significant, since deep-water corals are becoming increasingly studied for their role as framework builders for deep-water reefs, which are important as habitat for fish and other invertebrates. The NMNH is in a unique position to serve as a reference collection for identification of deep-water corals, zoogeographic analyses, and conservation advice. The jewel of the coral collection, however, is not a deep-water species, but the shallow water collection of corals made in the Indo-West Pacific by the U. S. Exploring Expedition in 1838-1842, which contains the types of most of the Pacific reef corals.

1. Lettuce coral Pavona cactus

   “Lettuce coral”, Pavona cactus, a common, delicate Indo-West Pacific reef coral. One of approximately 850 species of reef corals known in the world.

2. stylasterid hydrocoral

   The stylasterid hydrocoral Stylaster roseus is actually a calcified hydroid. Most hydrocorals have a colorful skeleton such as this one, but most are found in deep water. This is the only shallow water species (out of 42) known from the western Atlantic. Common in the reef environment. (USNM 98952)

3. Distichopora robusta

   Distichopora robusta is the only shallow water stylasterid in the eastern Pacific. Even though it occurs in shallow water and is brightly colored it was discovered and described only in 2004, one of the authors being a Smithsonian curator. This specimens is a female from the type series. (USNM 1020571)

4. Renilla mulleri

   A model of the sea pen Renilla mulleri, also called the “sea pansy”. These pelagic coelenterates are sometimes found floating by the million in the northern Gulf of Mexico.

5. Lepidisis sp.

   Skeletons of the deep-water bamboo coral, Lepidisis sp., common throughout the world at slope depths. The black nodes give the skeleton a certain degree of flexibility.

6. Heliopora coerulea

   The “blue coral”, Heliopora coerulea, is actually a highly calcified octocoral. It is so common in the Indo-West Pacific that in the 1980's it was collected and manufactured into simple jewelry, and called the “denim coral” because of its color. (USNM 45123)

7. Herpolitha limax

   Herpolitha limax (literally “creeping stone slug”) is a common Indo-Pacific colonial reef mushroom coral. Despite its large size and weight, because its skeleton is covered with tissue, this species can travel over hard substrates, attaining speeds of up to 2 cm and hour! (USNM 77722)

8. Flabellum impensum

   Flabellum impensum, named by Smithsonian curator Don Squires in 1961, is one of the largest of the solitary deepwater stony corals. This is one of about 15 species that occurs in sub-freezing waters off Antarctica. I think of it as the “Jimmy Carter smile coral”. (USNM 45666)

9. fossil coral

   Half of a fossil coral that was manufactured into a perfect sphere for museum sale. This one was sent to the Smithsonian by the Fish and Wildlife Service to determine whether the coral was fossil or Recent, the latter being illegal to transport and sell, the former not so.

10. Black coral

    Black coral can grow quite large (over 2 meters), along the reef face and drop offs in deep water. Commonly used to make jewerly and figurines. Coral collectors in the tropics can get over $100 for a pound of raw black coral.

11. Meandrina meandrites brasiliensis

    Meandrina meandrites brasiliensis, the “Brazilian maze coral”, is quite common in shallow water turtle grass regions in the western Atlantic. When alive, the tissue completely covers the skeleton.

12. Letepsammia formosissima

    Letepsammia formosissima (no common name) is one of approximately 650 species of deep-water stony corals, this one having a skeleton so delicate and porous that one can see through it. About 74% of the deep-water stony corals are solitary, as is this one. (USNM 81877)

13. Caryophyllia ambrosia

    Caryophyllia ambrosia (the “Caribbean horn coral”), another deep-water solitary stony coral, this one resembling in shape an ancient, now extinct, rugosan coral. (USNM 45921)

14. Stephanocyathus diadema

    Stephanocyathus diadema (literally the “crown-cup diadem”), is a deep-water solitary coral known from South Carolina to Brazil at depths of 800-2100 m. Few scleractinian (stony) corals have colored skeletons, this being a notable exception. (USNM 46321)

15. Turbinolia stephensoni

    left: an SEM picture of the smallest known stony coral, Turbinolia stephensoni, measuring only about 4 mm in height (x 22). right: an SEM of another stylasterid hydroid, Adelopora pseudothyron Cairns, 1982, this species having a hinged operculum that covers the cavity of each feeding polyp. This kind of operculum is unique in the animal kingdom, and measures about 0.5 mm in width (x80)

16. Stephanocyathus (A.) spiniger

    Stephanocyathus (A.) spiniger, another solitary, deep-water stony coral, this one having six long spines that slow it from sinking into soft substrates. (USNM 97132).

17. Deltocyathus calcar

    The deep-sea coral Deltocyathus calcar (the “snowflake coral”), this species occurring at slope depths (81-675 m) from North Carolina to Brazil. Sometimes hundreds of specimens are collected in the same net haul. (USNM 46267)

18. octocoral Corallium rubrum

    The skeleton of the octocoral Corallium rubrum (the precious pink coral), and a picture of some of the jewelry that is made from the skeleton. Because of its commercial value, at one time hundreds of dollars per pound, this coral was fished out of the shallow Mediterranean years ago. Divers, mainly via submersible, must now descend several hundred meters to obtain good specimens. Former Smithsonian curator F. M. Bayer was the authority of this genus, having described several of the species.